Undrtone - Social layer on top of Spotify and Rdio from Scott Vener
Apple Music - Apple Music app combines your personal iTunes library with Apple's music subscription service. Music you have purchased from the iTunes store, or synced over from other sources, is available in the "Library" tab. Read more about Apple Music.
PlaylistMap - Connect with Spotify playlist curators from around the world
ThinMusic - ThinMusic is a free web player for Apple Music with support for last.fm scrobbling.
BeatSense - Discover great music hand-picked by real people, in a single click. FREE and in real-time!
Apple Music Web App - Apple Music is now available to stream on the web